Preparation of cyclic hydroxylated siloxanes



United States Patent 3,268,570 PREPARATKON 0F CYCLIC HYDROXYLATEDSHLOXANES Donald R. Weyenberg, Midland, Mich., assignor to Dow CorningCorporation, Midland, Mich, a corporation of Michigan No Drawing. FiledMar. 29, 1962, Ser. No. 183,421 2 Claims. (Cl. 260-4482) This inventionrelates to novel cyclic siloxanes containing silicon-bonded hydroxylgroups.

It is the object of this invention to prepare new compositions of matterwhich are useful as water repellents and as intermediates in thepreparation of polymeric siloxanes.

This invention relates to compositions of the formula in which R is amonovalent hydrocarbon radical or a monovalent halohydrocarbon radicaland Y is OH or R at least one Y being R.

The compositions of this invention can be made by two methods. The firstmethod involves the reaction of a diol of the formula R Si(OH) with achlorosilane of the formula RSiCl in equimolar amounts in a mutualsolvent and in the presence of a hydrogen halide acceptor. Under theseconditions the diol reacts with the trichlorosilane to produce thetetrasiloxane of the formula This process is preferably employed toprepare symmetrical cycles.

The chlorine-containing cyclic is then hydrolyzed to the diol bydissolving it in a solvent and hydrolyzing carefully with water at lowtemperature. If desired, a hydrogen halide acceptor can also be employedin this hydrolysis step. In carrying out these reactions suitablesolvents include hydrocarbons such as petroleum ether, benzene, tolueneand xylene; ethers such as diethylet'her or dibutylether andhalohydrocarbons such as methylene chloride or perchloroethylene.Suitable hydrogen halide acceptors include ammonia, pyridine, a-picolineor quinoline.

A second method of preparing the cyclics of this invention is tocohydrolyze a clichlorosilaue of the formula R SiCI with adichlorosilane of the formula RHSiCI This hydrolysis is best carried outin solvent so as to promote the formation of cyclics. Under theseconditions mixed cyclic siloxanes are obtained having the formulae Thesemixed cyclosiloxanes can then be converted to the correspondingsiloxanols by reacting the SiH group with water in the presence ofcatalysts such as platinum, palladium, ruthenium and rhodium as is fullydescribed in the copending application Serial No. 183,419 of Garrett H.Barnes, Jr., and Robert L. Merker entitled A Method of PreparingSilanols filed concurrently herewith the entire disclosure of which isincorporated by reference. Briefly, this method involves the reaction ofthe SiI-I with HOH to give SiOH-l-H The reaction proceeds attemperatures ranging from below room temperature up to temperatureswhich will not cause condensation of the silanol groups to SiOSi.

For the purpose of this invention R can be any monovalent hydrocarbonradical such as alkyl radicals such as methyl, ethyl, butyl oroctadecyl; unsaturated aliphatic hydrocarbon radicals such as vinyl,allyl, hexenyl, ethynyl and butadienyl; cycloaliphatic hydrocarbonradicals such as cyclopentyl, cyclohexyl, cyclohexenyl,methylcyclohexenyl and B-cyclohexylethyl; aryl hydrocarbon radicals suchas phenyl, xenyl, naphthyl, anthracyl, tolyl or xylyl and aralkylhydrocarbon radicals such as benzyl, ,8- phenylethyl, andfl-penylpropyl. R can also be any haolgenated hydrocarbon radical suchas chloromethyl, gamma-chloropropyl, bromocyclohexyl, perfiuorovinyl,chlorocyclohexenyl, trifluoropropyl, pentafiuorobutyl, dibromophenyl,pentachlorophenyl, tetrabromoxenyl, 0t,ot,ottrifluorotolyl anddichlorodifluorocyclo'butyl.

The following examples are illustrative only and should not be construedas limiting the invention which is properly delineated in the appendedclaims. The abbreviations Me for methyl and Ph for phenyl are employedbelow.

Example 1 To 409 g. of methyltrichlorosilane in 700 cc. of dry benzenethere was added a solution of 216 g. of diphenylsilane diol in 158 g. ofpyridine and 300 cc. of benzene. The diol solution was added over aminute period at a temperature of 20 to C. The slurry was stirred onehour, filtered and washed with benzene. The solvent was then removed andthe residue distilled to give the cyclic siloxane boiling at 233 to 237C. at .3 mm.

A solution of 14.6 g. of this cyclic in ml. of ether was added to asolution of 200 cc. of diethylether, 4.05 cc. of pyridine, .9 cc. ofwater and cc. of acetone. The addition was carried out over a period of15 minutes and the resulting product was stirred for 30 minutes and thenpoured into ice water. The organic solvent solution was washed and thendried over sodium sulfate. The solvent was evaporated and the residuecrystallized on stirring in an equal volume of pentane. The crystallineproduct was recrystallized from a mixture of percent aliphatichydrocarbon and 30 percent benzene. The product melted at 129 to 137 C.and was composed of mixed cisand trans-isomers of the structure Example2 13.6 g. of the cyclic1,5-dimethyl-3,3,7,7-tetraphenylcyclotetrasiloxane was dissolved in ml.of dioxane and 9.5 ml. of water was added. The mixture was stirred at2.5 g. of a dispersion of 4 percent by weight palladium on charcoal wasadded in 5 increments over a two-day period. At the end of this time thetest for SiH was negative and the product was filtered and the solventremoved by evaporation. The solid product was recrystallized from twoliters of petroleum ether to give a crystalline product which was amixture of needles and granular crystals. These represented the twoisomers, namely the cisand trans-isomers. Each crystal form melted at148 to 149 C., however, a mix melting point on the needles and thegranules was found to have a melting point of 130 to 133 C. This productwas the cyclic 1,5-dimethyl-3,3,7,7-tetraphenylcyclotetrasiloxane-1,5-diol.

following diols in accordance with the procedure of Example 1 and theresulting cyclotetrasiloxanes are hydrolyzed in accordance with thatexample, the following cyclic diols are obtained:

When the following SiH containing cyclotetrasiloxanes are reacted withwater in accordance with the method of Example 2, the following productsare obtained:

Cyclic Product Cur-[ i O /C13H37 CQHK O 013E317 MeSli Si-H Mei-$1 S1-OHour- 0 o 00H (Jun 0 0 06H Me-Si\ /SiMe Me-Sl Si-Me 0 o 0 /CH2CHgCF oonionzom oraonzonmsi sin omonzonm si Si-OH I o oniongolu o onionzom(onomonms SiH (CF CHzOHzhSi Si-OH 0 0013413: 0 00mm rmsi Sit-H PhisiSIiOH r O t Ph Si SiPhz PhgSi SiPh: 0 o

O CoHmCl 0 06151001 fi i /i' i Me 0 0 Me 0 0 I I CFa I l/ CF; OlCH1u7Si\ si ClOoHurSi\ /Si 11 0 Me HO 0 Me i i Me Qanom Si Si onion- 3o11o112 Si Si CHzCH-O 2i i 7 2 i 2 o o o 0 I I IQeHQ K R ii i o H 2 0 onMe 0 01120112011201 e 0 01120112011101 CH3CH2CH2S|i s it-H CHaCH2CHzS|iS|i-OH I I I o1o112oHioH2 si /Si Me OlCHzCHzCHz7Si\ si Me o CHzCHzOH; no0 CHZCHQCH3 5 That which is claimed is: 1. A process for making a cyclicsiloxane of the formula in which each R is selected from the groupconsisting of 'monovalent hydrocarbon and monovalent halohydrocarbonradicals, comprising reacting a diol of the formula R Si(OH) with achlorosilane of the formula RSiCl in equimolar amounts in a mutualsolvent, and in the presence of a hydrogen chloride acceptor, and thenhydrolyzing the product so obtained.

References Cited by the Examiner UNITED STATES PATENTS 2,684,379 7/1954Guillissen et al 260-4482 2,954,391 9/1960 Riley ct a1 260-44823,037,962 6/1962 Hartung et al.

OTHER REFERENCES Eahorn, Organosilicon Compounds, Academic Press Inc,New York, publ., 1960, page 237.

Sokolov, Zhur. Obscheii Khim., vol, 29 (1959), pp. 24843.

TOBIAS E. LEVOW, Primary Examiner.

SAMUEL H. BLECH, Examiner.

I. G. LEVITT, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N0o3,268,570 August 23, 1966 Donald Ro Weyenberg It is hereby certifiedthat error appears in the above numbered patent requiring correction andthat the said Letters Patent should read as corrected below.

Column 4, Table 3, under the heading Cyclic diol, line 9, for "5,5-diol"read n l,5-diol 0 Signed and sealed this 22nd day of August 19670 AL)Attest:

ERNEST W. SWIDEB.

Attesting Officer EDWARD J. BRENNER Commissioner of Patents

2. A PROCESS FOR MAKING A CYCLIC SILOXANE OF THE FORMULA